555

Do you want help with 555 in one of these contexts? Here are quick notes in case you’re prepping for exams:

• Math (number 555)

  • Prime factorization: 555 = 3 × 5 × 37
  • Divisibility: divisible by 3 (sum of digits = 15), by 5; 555 = 15 × 37
  • In Roman numerals: 555 = DLV

• Electronics (555 timer IC)

  • Modes: astable, monostable, bistable
  • Astable frequency: f ≈ 1.44 / ((RA + 2 RB) C)
  • High time: TH = 0.693 (RA + RB) C
  • Low time: TL = 0.693 RB C

If you want, I can give you a couple practice problems or walk through a specific example. Which context are you studying?